Researchers from the world's largest brain bank devoted to studying the effects of repeated concussions on professional athletes released stunning, updated numbers on Friday: 96% of the brains from former National Football League players in their study showed signs of the brain disease chronic traumatic encephalopathy (CTE).
The new numbers, shared with Frontline, found that 87 out of 91 deceased NFL players whose bodies were donated to the study tested positive for CTE, a degenerative brain disease linked to repeated concussions like those suffered by football players.
Out of all football players who were sampled in the ongoing study — NFL, semi-pro, and student players — 131 out of 165 showed signs for CTE, a 79% positive rate.
The Department of Veterans Affairs, Boston University, and the Concussion Legacy Foundation conducted the study, funded in part with a $1 million grant from the NFL themselves.
"When we co-founded the VA-BU-CLF Brain Bank in 2008, there were only 4 known cases of CTE in former NFL players," said Chris Nowinski, founding executive director of the Concussion Legacy Foundation, in a statement to BuzzFeed News.
"The research team, led by Dr. Ann McKee, is conducting groundbreaking work that gives us hope we will one day have an effective treatment.
"We would like to thank the hundreds of families across North America that have donated the brain of a loved one to make this research possible, and welcome other families to learn more about ongoing research, including the brain donation program, at ConcussionFoundation.org," Nowinski said.
The study has to rely on posthumous donations of brains as there is still no effective way to test for CTE in living patients. The donated brains, by and large, come from players who were previously suspected of suffering from CTE. The lack of living test subjects and a reliance on a small sample size of brains are important caveats to the study, but researchers say the results are "remarkably consistent."
The NFL released a statement about the study saying they will continue efforts to improve player safety:
We are dedicated to making football safer and continue to take steps to protect players, including rule changes, advanced sideline technology, and expanded medical resources. We continue to make significant investments in independent research through our gifts to Boston University, the [National Institutes of Health] and other efforts to accelerate the science and understanding of these issues.
Symptoms of CTE include depression, memory loss, aggressive behavior, and impairment of motor skills. The NFL negotiated a settlement over the past year with thousands of former players to cover medical expenses and invest in prevention of CTE that could total $1 billion.
The NFL's handling of concussions and brain disease gained a national spotlight in 2013 with the release of the Frontline documentary League of Denial, which portrayed the NFL as being hostile towards CTE researchers and dismissive of the very existence of the disease. The documentary served as an inspiration for the upcoming Will Smith drama, Concussion.